Coupling, particularly for lng

ABSTRACT

In order to provide an operationally secure coupling for connecting a coupling housing ( 11 ) to a nipple, which are provided for feeding a cryogenic medium, particularly LNG, to a vehicle tank, a hand lever ( 15 ) is arranged in a pivotable way on the coupling housing ( 11 ) for the connection thereof. According to the invention, on the coupling housing ( 11 ) adjacent to the hand lever ( 15 ) a control block ( 20 ) having at least one locking element ( 21 ) is provided, which locks the hand lever ( 15 ) in the connecting position.

The invention relates to a coupling for connecting a coupling housing to a nipple, which are provided for feeding a cryogenic medium, in particular LNG to a vehicle tank, wherein a hand lever is pivotably arranged at the coupling housing for connecting.

There are known couplings for cryogenic mediums, which show several disadvantages concerning their connecting mechanics. DE 195 16 029 C1 or DE 4041337 A1 disclose couplings for cryogenic mediums, wherein the coupling plug is inserted into the quick coupling socket, such that the outside coupling housings overlap and a connecting element at the quick coupling socket engages with a counterpart arranged at the coupling plug, The connection is usually completed by time-consuming screwing of the coupling plug and the quick coupling socket. During this insertion of the coupling plug into the quick coupling socket, the coupling is first sealed against the environment and then the line end locks are opened.

Beyond that DE 41 04 711 A1 or U.S. Pat. No. 4,335,747 A1 show sealing against the environment by separate opening/closing of two ball valves. The connection of the coupling plug to the quick coupling socket is made by mechanical elements in the separating plane. The two ball valves must be separately opened or closed.

Further, the known couplings require high assembly expenditures. The plugging/pushing connection of the coupling housings needs high surface finish and form accuracy as well as high purity of the connecting surfaces, in order to connect with small forces. Likewise the plugging/pushing connection is not satisfactory as to safety, if the quick coupling socket (nipple) is a refuelling mechanism (tank lid) at the vehicle and the coupling plug is arranged at a fuel station, since the plugging connection can lead to heavy damages at the gas station and/or the vehicle when driving away in connected state. In addition, if refuelling of cryo-fuel containers of vehicles is made by laymen, operation of the coupling requires a simple and safe formation of the coupling, so that the operator does not come into contact with the deep-cold cryo-fuel. Thus, couplings for cryogenic mediums would be desirable, which avoid the disadvantages known from prior art.

The invention has the object to create a coupling for cryogenic mediums, in particular LNG, in order to improve operating safety over known couplings.

This object is achieved according to the invention with a coupling having the features of the claim 1. Favourable embodiments of the invention are stated in the sub-claims.

The handling and safety of the suggested coupling is substantially improved, since a locking element is actuated by the pivotal movement of the hand lever on connection to the nipple, preferably via collets, thus locking the hand lever in the connecting position. Any unintentional loosening of the coupling can thus be excluded in a safe manner.

By the operation of the coupling according to the invention also the control of the flow path of the cryogenic medium to the nipple is achieved in type of a safe sequencing. The latch of the coupling takes place in a separate step before. The same applies to uncoupling, so that it is ensured that the operator of the coupling does not come into contact with the cryogenic medium, which is reliably shut-off before unlocking of the hand lever by the control block and the control bar coupled thereto.

The simple structured control bar includes in particular a metal bellow, whose interior is connected to a control line. The control line can be opened or closed via a control signal, as described in EP 0 889 273 A1.

An embodiment of the invention is shown in the drawing shown and described in the following in detail. Here show:

FIG. 1 a perspective view of a coupling;

FIG. 2 a side view on the coupling housing;

FIG. 3 a longitudinal section of coupling shown in FIG. 2 in horizontal plane; and

FIG. 4 a longitudinal section of a control block in horizontal plane.

The coupling 1 shown in perspective view in FIG. 1 includes a coupling housing 11 for connecting two line ends. The connection of the coupling housing 11 to a coupling nipple (here not represented) is made by several locking elements in the form of collets 30. For this purpose a hand lever 15 is provided at the coupling housing 11, which is pivotally mounted at an axis 16 and a relatively short spreading lever 17 is pivotally mounted adjacent to the axis 21. On moving the hand lever 15 the required mechanical force is provided, which pulls the coupling housing 11 against the coupling-flat of the nipple provided with seals, wherein the spreading lever 17 achieves a power amplification in type of a toggle joint. Thus, a relative small hand strength is sufficient in order to establish the coupling connection.

When swivelling the hand lever 15 (cf. arrow in FIG. 2), first, a lock sleeve 31 is shifted over the collets 30, here to the left, to lock these in a positive manner, as described in several patents of the Applicants (e. g. EP 1 483 524 B1; internal Ref.: S 0041-P-EP). On the other hand, when swivelling the hand lever 15 to a control block 20, which is fitted onto the coupling housing 11 or integrally formed with this, a laterally projecting operation knob 22 is actuated. This operates a valve in the control block 20 (cf. FIG. 4), so that an input pressure at a pressure line P, e. g. compressed air at 5 bar, pushes at least a locking element 21 in the control block 20 outwards, thus preventing movement of the hand lever 15 in this connection position. The locking element 21 is preferably arranged at both sides of the control block 20 in the form of symmetrically extensible check pistons 21 a (cf. FIG. 4). FIG. 1 further shows a main line 47 for feeding of the medium, likewise in FIG. 2 in side view, also indicating the section planes for. FIG. 3 and FIG. 4 with A and B.

As apparent from the longitudinal section in FIG. 3 (in horizontal central plane) a generally tubular coupling housing 11 forms an insulation chamber to prevent evaporation of deep-cold mediums, like LNG in the line ends. The line ends lead to the parting plane of the coupling nipple (that is preferably connected to a fuel tank) and of the coupling housing 11, which surrounds the main line 47 at least partially. At each line end opposite valves are arranged to open or close the line ends adjacent to the respective front surfaces thereof, e.g. in the coupling housing 11 at least one seal 38 is formed of PTFE.

In order to open or close the supply at the coupling housing 11 a control bar 36 is provided, which preferably also carries a seal from PTFE. The control bar 36 is urged to a sealing surface via a compression spring 41 and also by a metal bellow 44 connected thereto. The metal bellow 44 includes an interior chamber 45, which is connected to a pressure generator (not represented) via a control line 46. Pressurized control fluid (e. g. compressed air at 10 bar) is supplied to the interior 45 via the control line 46, so that the metal bellow 44 is extended in axial direction to open the medium or fluid inlet by the control bar 36.

On swivelling the hand lever 15 to the control block 20 and the force amplification mechanism of the spreading lever 17 the coupling nipple and the coupling housing 11 are pressed to each other and solidly locked in a positive manner by the collets 30. In this tight position flow of the cryogenic medium is not possible, yet. Only by switching the actuating pressure via the control line 46 the interior 45 of the bellow 44 is supplied with pressure. Then, the bellow moves the control bar 36 holding the seal 38 towards the nipple side. Thus, the coupling housing 11 and the coupling nipple are in open positions. The two line ends are now connected with each other and the cryogenic medium can flow.

Releasing of the actuating pressure at the control line 46 (and thus the subsequent release of the fluid flow in the main line 47) is preferably made by a return line R at the control block 20, as shown in FIG. 4, i. e. only after the locking element 21 or the check pistons 21 a have “blocked” the hand lever 15 in the connecting position. Thus, a particularly high connection security is achieved.

After completion of the medium flow (f. i. a certain filling amount of the fuel tank is achieved via the nipple) the interior 45 is balanced by means of the control line 46. Thus, the compression spring 41 pushes the control bar 36 and the metal bellow 44 into the closed position of the coupling. This is supported by the pressure in both line ends, since effective bellow and sealing surfaces cause additional closing forces. At the same time or with a small time delay the pressure at the pressure line P is also switched off, so that the check pistons 21 a retract towards the interior of the control block 20 and thus the hand lever 15 can be tilted up into its home position. Then, the lock sleeve 31 is simultaneously withdrawn and the coupling is separated, again.

For confirming or acknowledgement of the flow disconnection a signal can be transmitted via the return line R on switching-off the pressure P at the control block 20, whereby the safety standard is further increased. This can be in form of a visual indication for the operator (e.g. “You can pay now/start”) or a release (“green light”) for the gas station personnel or an acoustic signal or an electronic unblocking (e.g. open a gate at the gas station). 

1. A coupling for connecting a coupling housing to a nipple, which are provided for feeding a cryogenic medium, in particular LNG to a vehicle tank, wherein a hand lever is pivotably arranged at the coupling housing for connecting, wherein a control block is arranged at the coupling housing adjacent to the hand lever and includes at least one locking element, which locks the hand lever in connecting position.
 2. The coupling according to claim 1, wherein the locking element is formed as a check piston being extensible in transverse direction to the pivoting plane of the hand lever.
 3. The coupling according to claim 1, wherein the control block includes two locking elements aligned in opposite directions.
 4. The coupling according to claim 1, wherein the control block is fitted onto the coupling housing.
 5. The coupling according to claim 1, wherein a control bar having a front seal is arranged in the coupling housing in a slidable manner and directed to the nipple.
 6. The coupling according to claim 5, wherein the control bar is surrounded by a compression spring.
 7. The coupling according to claim 1, wherein the coupling housing includes several, in particular six collets.
 8. The coupling according to claim 7, wherein the collets are surrounded by a lock sleeve, which supports one end of the hand lever.
 9. The coupling according to claim 1, wherein a spreading lever is hinged at the hand lever close to its pivot axis and connected to the coupling housing with the other end.
 10. The coupling according to claim 1, wherein the control block includes an operation knob, which is forced by the hand lever in connecting position.
 11. The coupling according to claim 1, wherein the control bar is forced by a bellow, preferably metal bellow, which is connected to a control line. 